The injections seem like....a bad idea. At least for those that the Empire find trustworthy. One vengeful impulse from a mage and everyone dies. From an OOC standpoint, we know no one will do that, but from the Empire's perspective, they didn't even know Landvarian could SPEAK, much less any of the magi's true intentions once they are free of their cells with a chance to kill some of their jailors, even with the knowledge that it would be killing a few other magi. Justifications can be made for many things...